Refractory high entropy TiTaZrHfW-N/Si3-N4 nano-layered alloy thin films are investigated to study the effect of nano-layered architecture and silicon (Si) mean content on their structural, mechanical, thermal properties and oxidation behavior. The films are deposited using direct current (DC) magnetron sputtering of separate Si and TiTaZrHfW targets. The Si mean content is controlled by tailoring the power discharge applied to the Si target. The deposition process led to a nano-layered architecture where Si3N4 (amorphous) and TiTaZrHfW-N (nanocrystalized NaCl FCC type structure) are alternated. By increasing the thickness of Si3N4 nano-layers, the Si mean content increases. All coatings are found to have good thermal stability after annealing under vacuum at 900 degrees C. Increasing Si mean content reduces the film's hardness; however, the annealing treatment at 900 degrees C improves it. A super-hardness of 41 GPa is found for the post-annealed Si-free film. Si3N4 nano-layers enhance the oxidation resistance at elevated temperatures of 600, 700, and 800 degrees C. This oxidation resistance is further enhanced by increasing the nano-layer's period and also by increasing the density of the films.

To decrease the volatilization rate of Cr on AISI 441 interconnect for Solid Oxide Cells (SOC) application, Mn0.5Co0.5O coatings were deposited using Reactive High Power Impulse Magnetron Sputtering (R-HiPIMS). Three different coating morphologies and preferential growth orientations were obtained by varying bias and temperature settings. All synthetized Mn0.5Co0.5O coatings reduced the volatilization rate of Cr during exposure in dry air at 800 degrees C for 2000 h. Moreover, the Cr retention power was influenced by the preferential growth orientation of the coating. This study suggests that the deposition parameters of R-HiPIMS can be adjusted to optimize the crystalline orientation and enhance the effectiveness of Mn-Co oxide coatings as barriers against chromium volatilization.

This work uses the direct current magnetron sputtering (DCMS) of equi-atomic (AlTiZrHfTa) and Si targets in dynamic sweep mode to deposit nano-layered (AlTiZrHfTa)Nx/SiNx refractory high-entropy coatings (RHECs). Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to investigate the effect of Si addition on the oxidation behavior of the nano-layered coatings. The Si-free nitride coating exhibits FCC structure and columnar morphology, while the Si-doped nitride coatings present a FCC (AlTiZrHfTa)N/amorphous-SiNx nano-layered architecture. The hardness decreases from 24.3 ± 1.0 GPa to 17.5 ± 1.0 GPa because of the nano-layered architecture, whilst Young’s modulus reduces from 188.0 ± 1.0 GPa to roughly 162.4 ± 1.0 GPa. By increasing the thickness of the SiNx nano-layer, kp values decrease significantly from 3.36 × 10−8 g2 cm−4 h−1 to 6.06 × 10−9 g2 cm−4 h−1. The activation energy increases from 90.8 kJ·mol−1 for (AlTiZrHfTa)Nx nitride coating to 126.52 kJ·mol−1 for the (AlTiZrHfTa)Nx/SiNx nano-layered coating. The formation of a FCC (AlTiZrHfTa)-Nx/a-SiNx nano-layered architecture results in the improvement of the resistance to oxidation at high temperature.

Coatings play a key role in modern industry, enhancing the performance of materials. The diversity of their applications and constant progress make them a central area of research and development in materials science and engineering. In this manuscript, we examined some recent works of high-entropy coatings deposited by magnetron sputtering. The first section provides details on the magnetron sputtering technique and deposition mechanism. The change of the parameter influences the microstructure and then the properties of the films. High Power Impulse Magnetron Sputtering is sued to increase the compactness of the film. In the second, a spotlight on High-Entropy Films (HEFs) as an emergent-class material is presented and how their oxidation resistance is improved. Particular attention is being paid to studying the effect of some alloying elements, such as nitrogen and silicon, on oxidation resistance improvement. The last section presents potential applications of these coatings, especially the cutting tools, the diffusion barrier, and other industrial uses.

(AlTiZrHfTa)1-xNx refractory high entropy films (RHEFs) were deposited by direct current magnetron sputtering in various nitrogen ratios (RN2 = N2/(Ar+N2)) on flat glass, silicon and sapphire substrates. The nitrogen-free film is amorphous while the nitrides are single-phased solid solutions with Face-Centered Cubic (FCC) structures. The hardness increases from 6.4 GPa for the nitrogen-free film to 25.3 GPa for the film obtained at RN2 = 20%. A preferred orientation from (111) to (200) occurs when RN2 increases from 5% to 50%. H/E and H3/H2 reports show high values for the film deposited at RN2 = 20% compared to that at 10%. However, this latter has the best compromise in terms of mechanical properties related to a lower residual stress value. The nitrides films obtained with RN2 >= 5%, are thermally stable at 800 degrees C for 3 h under vacuum. Compared to the metallic film they show an improved oxidation resistance. In fact, the Kp constant of the nitride (RN2=20%) is lower (1.22 10-7 g2 cm-4 h-1) than that of the nitrogen-free film (1.77 10-6 g2 cm-4 h-1). The corresponding activation energies (Ea) are respectively calculated at 94.8 KJ. mol-1 and 45.5 KJ.mol- 1. After oxidation process, TEM analysis reveal the formation of homogeneous mixed oxide.

In this work, TiN/Ti(C,N)/Al2O3 multilayer coatings were deposited using an industrial-scale thermal CVD system. Two polymorphs of Al2O3, the stable α- and the metastable κ-Al2O3, were obtained by the deposition of specific bonding layers at the Al2O3/Ti(C,N) interface. The comparable hardness and elastic moduli of α- and κ-Al2O3 multilayer coatings were measured. The tribological behavior of Al2O3 multilayer coatings was studied at room temperature using 24CrMoV5-1 balls; friction coefficients were comparable for both α- and κ-Al2O3 multilayer coatings. As a result of the relatively high hardness of coatings and the generation of abrasive wear particles, larger wear tracks were observed on balls. In Rockwell C tests, good adhesion at Al2O3/Ti(C,N)-based layer’s interface was reported in κ-Al2O3 multilayer coatings, which could be attributed to the deposition of κ-bonding layers consisting of needle-shaped grains. The cutting performances in the turning-roughing of 24CrMoV5-1 steel under different parameters—cutting speed, feed, and depth of cut—were investigated. Herein, κ-Al2O3 multilayer coatings showed the longest tool life, double of that of a commercial CVD Al2O3 multilayer coating. The results obtained could enrich the existing database for the development of prediction models of tool wear and machined surface quality and help improve tool performance for the machining of 24CrMoV5-1 steel.

Improving the properties of materials used in engineering and in industry is the main axe of materials science [...]

In the last decades, refractory high entropy thin films have attracted more attention due to their superior properties at high temperatures. Besides the thermal stability, these new materials present good mechanical properties at high temperatures, which is interesting compared to conventional alloys. TiTaZrHfW(-N) films are deposited by reactive magnetron sputtering in various argon/nitrogen atmospheres. Optical emission spectroscopy is performed to analyze the target poisoning conditions and optimize the deposition parameters. The nitrogen flow rate ratio RN = phi N2/(phi N2 + phi Ar) is varied from 0 to 29 %. XRD analyses show a phase transition from amorphous to B1(NaCl) single phased films once the nitrogen is added. For all nitrides, an out-of-plane {111} preferential orientation is observed, except for RN = 9 %, for which it changes to {200}. The morphology of the films changes from compact to columnar when the nitrogen ratio exceeds 5 %. The hardness and Young's modulus are also studied and present evolution with maximum values, 29 GPa and 257 GPa for RN = 9 % respectively. All nitrides show good thermal stability under vacuum at 800 degrees C for 3 h, compared to nitrogen-free metallic film, for which phase transition occurs. Nitrides show improved oxidation resistance compared to that of metallic film.

In this study, we aim to investigate the effect of zinc interstitials (Zni) and oxygen vacancies (VO) on the ZnO electrical conductivity. ZnO films were synthesized via DC magnetron sputtering process using pure Zn target in gases mixture of Ar/O2 = 80/17.5 (sccm). In order to improve the optical and electrical prosperities, the obtained films were subjected to air and vacuum annealing treatment. Several techniques such as field emission scanning electron microscopy (FESEM), Grazing Incidence X-ray Diffraction (GIXRD), Raman spectroscopy, photoluminescence spectroscopy (PL) and UV-visible were used to study the influence of heat treatment on structural and physical properties of ZnO films. Electrical conductivity of ZnO thin films was determined by measuring the sheet resistance and thickness of the films. XRD results confirm the synthesis of annealed ZnO films of the hexagonal structure with a preferential orientation along the (002) plane. The average crystallite size is altered between 22.6 to 28.4 nm dependent on the plan orientation of the ZnO film. Morphology and crystallinity of the ZnO structure could efficiently control the transmittance, electrical resistivity and optical band gap. As deposited ZnO film showed a lower electrical resistivity of 2.72×10-3 Ωcm due to the Zn-rich conditions. Under vacuum annealing, a combination of low resistivity (1.17×10-2 Ωcm) and better optical transmittance (87 %) are obtained. ZnO films developed in this study with high transmittance and low resistivity and good electro-optical quality supports their use in transparent and conductive electrode applications. The plan presentation was visualized using Vesta, with the lattice parameter set as follows: a = b = 3.249 Å; c = 5.207 Å; α = β = 90°; γ = 120°. Based on the construction and optimization of primitive cells, the supercells were constructed and then optimized. Finally, (002) and (103) planes were cut and the planar supercell structure was constructed. In order to make a plane representation for the solid bulk with 10 Å of thickness.

This work introduces a new way to create 3D printed strain gauges by Direct Paste Deposition. This process is based on various steps of deposition of inorganic materials onto metallic substrates. These materials are based on the alkali activation principle, allowing to reach high temperature application ranges without high thermal treatment of solidification. Two materials are used to build a stacking of insulative and conductive layers to obtain an anisotropic conductive pattern. The use of such materials makes it compatible with tools operating at high temperature environments (over 400 degree Celsius). Rheological analysis has shown the compatibility of the extruded paste with extrusion processes. To ensure critical size control of the conductive pattern, the paste rheology and the printing parameters have been optimized. Electrical resistivity of the pattern have been characterized. The process of direct paste deposition makes the printing of strain gauges compatible with additively manufactured products and opens the opportunity to integrate electronics onto and/or into complex objects.

Refractory high-entropy films (RHEFs) are a new type of high-temperature material with great prospects for applications due to their superior properties. They have the potential to replace nickel-based superalloys in order to develop a new generation of materials that can be used under extreme conditions. (TiTaZrHf)100−xYx RHEFs are prepared using the magnetron sputtering technique. The yttrium (Y) content varies from 0 to 56 at.%. XRD analysis indicates the formation of an amorphous phase in Y-free films, while new phases are formed after the addition of Y. The results are confirmed by TEM analysis, revealing the formation of nano-grains with two phases L12 and Y-P6/mmm structure. With an increasing Y content, the grain size of the nano-grains increases, which has a significant effect on the mechanical properties of the films. Hardness decreases from 9.7 GPa to 5 GPa when the Y amount increases. A similar trend is observed for the Young’s modulus, ranging from 111.6 to 82 GPa. A smooth and featureless morphology is observed on the low Y content films, while those with a larger Y content appear columnar near the substrate. Furthermore, the phase evolution is evaluated by calculating the thermodynamic criteria ΔHmix, ΔSmix, Ω, and δ. The calculation results predict the formation of new phases and are then in good agreement with the experimental characterization.

Refractory high-entropy films (RHEFs), as multi-component materials, have garnered significant attention due to their potential use in high-temperature applications. RHEFs are endowed with unique microstructural and functional properties due to the use of refractory elements. In this review, we examine the recent state of research on RHEFs deposited by the magnetron sputtering technique. The microstructure of RHEFs has been analyzed/explored and the mechanical properties as well as the main hardening mechanisms of these films are discussed. Furthermore, functional properties such as resistance to corrosion and wear, electrical and irradiation performances, and high-temperature oxidation were evaluated. RHEFs can meet market demand in the field of engineering materials. However, many challenges, such as low ductility at room temperature, remain to be overcome. This review provides an overview of the strengths and weaknesses of RHEFs produced using magnetron sputtering.

This work aims at understanding the nucleation and growth of alumina films grown on Ti(C,N)-based layers using an industrial-scale CVD system. Firstly, Al2O3 layer was deposited on Ti(C,N)-based layers without any nucleation treatment, pure α-Al2O3 is obtained, whereas no orientation relationship at the Ti(C,N)/α-Al2O3 layers interface can be observed. Secondly, Al2O3 layer was deposited on the bonding layer consisting of rutile TiO2, which is obtained by oxidizing the uppermost part of Ti(C,N)-based layers. Herein, α-Al2O3 single-phased layer is obtained, and the epitaxial growth of α-Al2O3 on rutile is observed. The orientation relationships can be found as:(1¯20)α-Al2O3//(101¯)rutile, (003)α-Al2O3//(010)rutile and [210]α-Al2O3//[101]rutile. Finally, Al2O3 layer was deposited on the bonding layer, produced from a TiCl4-H2-N2-CH4-CO-AlCl3 gas mixture. Regarding this intermediate layer, despite additions of CO and AlCl3, no evidence for oxide phases, e.g. TiO2 and Al2O3 can be found, while Ti(C,N) needle-shaped grains develop. In this case, κ-Al2O3 is epitaxially grown on Ti(C,N), with the orientation relationships found as:.(01¯3)κ-Al2O3//(2¯20)Ti(C,N), (100)κ-Al2O3//(1¯1¯1)Ti(C,N) and [031]κ-Al2O3//[112]Ti(C,N). Since processing parameters for the alumina depositions were always the same, it is revealed that the nucleation of α-Al2O3 and κ-Al2O3 can be accurately controlled with deposition of specific bonding layers.

The last decade has seen emerged numeric transition in industry, bringing new building blocks: Internet of Things (IoT) and additive manufacturing. A whole big new challenge was born based on sensors integration with the capability to bring intelligence into objects leveraging on additive manufacturing topological optimization, and thus operating in harsh environment thanks to efficient packaging. This work presents a new way to create 3D printed electronic patterns, based on Paste Extrusion Modeling (also called Direct Ink Writing) to extrude a superposition of insulator and conductive inorganic materials. Their raw compositions were characterized through EDS and XRD and compared to their datasheets. The obtained patterns show great electrical behavior under mechanical oscillation, opening possibilities for strain measurement.

There is a growing interest in the design of high entropy alloys due to their remarkable properties and applications in various fields such as aerospace, medical and automotive. AlTiTaZrHf(-N) high entropy metalsublattice nitrides were deposited in various argon-nitrogen gas mixtures on glass and silicon substrates. X-ray diffraction analyses reveal a transition from amorphous to an FCC single phase by increasing the nitrogen content. The films have compact or columnar morphology depending on the nitrogen flow rate. Energy dispersive spectroscopy analysis shows a decreasing of the matals content as the nitrogen flow rates ratio R-N2 = N-2/Ar + N-2 increases. XPS surface analysis reveal the formation of nitrides when the nitrogen is introduced. Evolution of hardness and Young's modulus are discussed and the maximum values are obtained for a flow rates ratio R-N2 of 10% at 27.67 GPa and 205.56 GPa respectively. The same film reveals good tribological properties compared to other films. This work conclusively demonstrates that high entropy metal-sublattice nitrides can be generated in an efficient way with tunable properties.

The data presented in this article are related to the published research of “Effect of nitrogen content on structural and mechanical properties of AlTiZrTaHf(-N) high entropy films deposited by reactive magnetron sputtering”. This database contains X-ray photoelectron spectroscopy (XPS) measurements, performed in order to determine the extents of nitrides formed in AlTiTaZrHf high entropy films. The latter were prepared by DC magnetron sputtering technique in reactive mode by adding the nitrogen to argon gas. The nitrogen flow rate is calculated by RN2 = N2/(N2+Ar). XPS measurements were done one month later. Oxides were detected on the top surface of the samples. 2p, 3d and 4f core level peaks were fitted in order to determine accurately the chemical composition of the nitride films. Al2p, Ti2p, Zr3d, Ta4f, and Hf4f reveal the formation of nitrides of all elements constituting the films. Atomic percentage of each element was calculated revealing an increase of nitrogen loading and decrease of the metallic fractions of the elements as RN2 grows from 5% to 50%. Nitridation behaviour of each element, as a function of the nitrogen flow rate, is investigated and presented.

High-entropy films (HEFs) are of considerable interest in surface engineering applications due to their superior properties, such as good corrosion resistance, good thermal stability and excellent high temperature oxidation. Recently, the scientific community has seen an increasing development of the multicomponent coatings, improving their properties compared to conventional films. Technically, different strategies have been exploited to fabricate HEFs. Magnetron-sputtered HEFs have made significant advancements in this field. HEFs have various applications given their interesting performances. This article overviews the development and the outcome of HEFs prepared using the magnetron sputtering technique. The classification of HEFs is reported. The effect of magnetron sputtering parameters on the microstructural, mechanical, electrochemical and thermal properties of HEFs is also discussed. Applications of HEFs are reported in the last section.

Using an industrial-scale chemical vapor deposition (CVD) system, a series of Ti(C,N) films were deposited from a TiCl4-CH3CN-H-2-N-2 gas mixture at 850-950 degrees C and 70-700 mbar with N-2/H-2 molar ratio varying from 0.27 to 3.77. Within the investigated temperature range, it is found that the growth rate of Ti(C,N) films is strongly dependent on the total pressure. Such behavior agrees with a diffusional limitation step. The lowest growth rate is measured at the N-2/H-2 molar ratio of 3.77, because of the low reduction rate of TiCl4 in a H-2 deficient atmosphere. No significant influence of processing conditions on the carbon content of Ti(C,N) films could be found, as determined by X-ray diffraction and EPMA. The microstructure and mechanical properties were investigated and chiefly influenced by deposition conditions. In this work, the Ti(C,N) films deposited at 850 degrees C and 70 mbar with N-2/H-2 molar ratio of 0.27 exhibit a mixed texture with laminated facetted grains, the superior hardness reaching 30 GPa and the Young's modulus of 394 +/- 32 GPa were measured. Furthermore, experimental results reveal that residual stresses could be thickness-dependent, due to the evolutionary film microstructure during film growth, and the stress relaxation is particularly attributed to cooling cracks.

Surface coating is of a great interest to increase the performances of the materials and extend its lifetime. High entropy films (HEFs) become the hot spot for developing surface engineering applications due to their good performances. They are reported to have superior properties such as good corrosion, wear resistance and excellent high temperature oxidation. Various deposition techniques have been exploited to fabricate HEFs such as laser cladding, spraying, sputter deposition and electrochemical deposition. These techniques are known to be an easy process to achieve a rapid quenching. Magnetron sputtering is seen as the most efficient methods to deposit the HEFs. Different gas can be used to prepare the ceramic materials. Besides, the deposition parameters reveal a strong influence on the physicochemical properties of HEFs. Working pressure, substrate temperature, bias voltage and gas mixture flow ratios have been reported to influence the morphology, microstructure, and functional properties of HEFs. The chapter overviews the development of the recent HEFs prepared by magnetron sputtering technique. First, it describes the principal of the technique. Then, it reports the classes of HEFs followed by the effect of the deposition parameters on their different properties. Applications have been developed using some HEFs for biomaterials and machining process.